n-bee-r,
Please check two things:
1. Tab on the OBiTALK icon at the bottom of the App Screen, and check
if the Voice Gateway shows the OBi number that you configured.
If it is blank or not the one you expected, then you can add back the correct number
and try login again from the app.
2. Otherwise, on the OBi that is your gateway, check under OBiTALK Service - InboundCallRoute
parameter value; make sure it still has the rule {(290xxxxxx)>(xx.):sp1}